Clot buster holds hope for treating COVID-19

Researchers from Australia’s Heart Research Institute (HRI) have developed an anti-clotting medicine with the potential to treat one of the most devastating, life-threatening complications of COVID-19 — microscopic blood clots.

Clinicians on the frontline have noted that COVID-19 can unleash a devastating storm of blood clots that cause breathing difficulties, stroke, heart attack and death, and have identified the critical role of blood clots in converting COVID-19 from a mild respiratory disorder into a devastating, life-threatening disease.

Severe COVID-19 infection leading to respiratory failure is associated with the development of widespread blood clots throughout the lungs. With up to 75% of ICU patients with COVID-19 developing these blood clots, preventing or dissolving them quickly may be the key to preventing death and long-term organ damage.

According to Sydney cardiologist Professor Ben Freedman, the extent of the blood clotting problem in COVID-19 patients was unexpected.

“Recent evidence from the Mount Sinai Hospital, New York, suggests that anti-clotting therapies may be our best option to prevent lethal complications from this devastating disease,” he said.

Existing treatments for blood clots forming in COVID-19 patients appear to be only partially effective and may increase the risk of bleeding side effects. The current recovery rate for critically ill COVID-19 patients who develop blood clots is low, with patients often placed on ventilators until their death. However, the new anti-clotting drug developed by HRI scientists is effective in preventing the formation and breakup of newly formed blood clots. The treatment has demonstrated a favourable safety profile when used in combination with existing blood-clotting drugs.

HRI Scientific Director and lead thrombosis researcher Professor Shaun Jackson has been working with his team for over 20 years on a drug that targets and dissolves blood clots safely, with a view to use the drug to treat stroke. He says COVID-19 presents a unique opportunity for the breakthrough treatment and the patients it helps.

“A great outcome from our clinical trials would be to see critically ill COVID-19 patients reaching for the tissue box instead of the ventilator,” Professor Jackson said.

“This current global pandemic has increased the urgency to get our drug trialled in patients and onto the market as soon as possible.”

The need for clinical trials

The aim of HRI’s clinical trials is to optimise the safety and effectiveness of its anti-clotting therapy in COVID-19 patients, to improve the breakdown of clots in the lung and to increase the anti-clotting benefits of heparin to prevent respiratory failure. As well as having the potential to save thousands of lives from COVID-19, the treatment has scope for treating patients with stroke or heart disease.

Following successful phase 1 trials that demonstrated the drug’s safety in otherwise healthy patients, the researchers want to progress urgently to global phase 2 trials, testing the effectiveness and safety of the drug in critically ill COVID-19 patients. This means that it could be a matter of months before doctors around the world can use the novel anti-clotting drug to protect patients with COVID-19, potentially saving thousands of lives.

“A really unexpected problem in patients with COVID-19 is a complication of stroke, and not necessarily just in the elderly,” said Professor Chris Levi, a leading stroke neurologist at UNSW and Chair of the Australian Health Research Alliance.

“New anti-clotting approaches to prevent this are urgently needed.”

Professor Jackson added, “We were on a great trajectory with this anti-clotting drug for use in stroke victims, though now COVID-19 has created a true, immediate emergency.”

He explained that the treatment holds considerable promise for protecting COVID-19 patients from one of the most aggressive blood clotting disorders ever identified. “Given the devastation caused by widespread blood clotting, we believe it is vital that we run a clinical trial as soon as possible in high-risk COVID-19 patients,” Professor Jackson said.

Blood clots: search and destroy

The anti-clotting treatment developed by HRI is not being repurposed for the novel coronavirus. Despite being initially developed by the thrombosis research team to target blood clots in stroke victims, it is still doing what it was made to do — targeting and dissolving blood clots in the body.

“We believe this anti-clotting drug represents a real opportunity for Australia to come to the world’s aid and help fight the complications caused by this aggressive disease,” Professor Jackson said.

Image caption: The thrombosis research team at HRI.